The Hidden Reality: Parallel Universes and the Deep Laws of the Cosmos

by Brian Greene

Note that the reasoning would fall flat if our universe were unique because you could still ask the “lucky coincidence” or “deeper explanation” questions. Much as a potent explanation for why the shop has your shoe size requires that the shelves be stocked with many different sizes, and much as a potent explanation for why there’s a planet situated at a bio-friendly distance from its host star requires planets orbiting their stars at many different distances, so a potent explanation of nature’s constants requires a vast assortment of universes endowed with many different values for those constants. Only in this setting—a multiverse, and a robust one at that—does anthropic reasoning have the capacity to make the mysterious mundane.*

The reasoning here is plain awful and the analogy terrible. A better analogy would be if your shoe size were 2,765.990651 while the manufacturer only produced up to 14. No matter how many ways you packed the store, the chances of finding a show that fit would be nil. Therefore, if you find your size, you rightfully conclude that someone intentionally created those shoes and placed them there.

But what kind of multiverse will guarantee, or at least make it highly likely, that this is the case?

This is the first example of the multiverse as a philosophical crutch to naturalism. It is imaginatively posited and presented as a "practical" necessity.

To think this through, consider first an analogous problem with simpler numbers. Imagine you work for the notorious film producer Harvey W. Einstein, who has asked you to put out a casting call for the lead in his new indie, Pulp Friction. “How tall do you want him?” you ask. “I dunno. Taller than a meter, less than two. But you better make sure whatever height I decide, there’s someone who fits the bill.” You’re tempted to correct your boss, noting that because of quantum uncertainty he really doesn’t need to have every height represented but, thinking back on what happened to the surly little talking fly who tried that, you refrain. Now you face a decision. How many actors should you have at the audition? You reason: If W. measures heights to a centimeter’s accuracy, there are a hundred different possibilities between one and two meters. So you need at least a hundred actors. But since some actors who show up may have the same height, leaving other heights unrepresented, you’d better gather more than a hundred. To be safe, maybe you should put out a call for a few hundred actors. That’s a lot, but fewer than what you’d need if W. measured heights to a millimeter’s accuracy. In that case, there’d be a thousand different heights between one and two meters, so to be safe you’d need to gather a few thousand actors.

Agh. This is just plain awful. A better analogy would be if W, in between assaulting various actresses, asked for someone 1000 feet tall. You could gather a million possibilities and you're chances are no better than if you stopped at ten.

This is just what the doctor ordered. Having 10500 tick marks distributed across a range from 0 to 1 ensures that many of them lie extremely close to the value of the cosmological constant astronomers have measured during the past decade. It may be hard to find the explicit examples among the 10500 possibilities, because even if today’s fastest computers took a single second to analyze each form for the extra dimensions, after a billion years only a paltry 1032 examples would have been examined. But this reasoning suggests strongly that they exist.

This presumes the tick marks are equally distributed across the spectrum--and therefore completely misses the point.

In judging any development, including multiverse theories, we must take account not only of its capacity for revealing hidden truths but also of its impact on the questions we are led to address.

In other words, if it allows us to preserve our preferred results by asking a question that predestines those results, it should be accepted. If it precludes such a question, it should be rejected.

In the twentieth century, fundamental science came to increasingly rely on inaccessible features.

Indirect and inaccessible are two separate things and can't be used interchangeably.

Even though such waves are its hallmark feature, we will see in Chapter 8 that the architecture of quantum physics ensures that they’re permanently and completely unobservable.

Convenient. How can you prove a negative like this, let alone the thing's positive existence if you believe it to be totally inaccessible?

Objects that have always been beyond our cosmic horizon are objects that we have never observed and never will observe; conversely, they have never observed us, and never will. Objects that at some time in the past were within our cosmic horizon but have been dragged beyond it by spatial expansion are objects that we once could see but never will again. Yet I think we can agree that such objects are as real as anything tangible, and so are the realms they inhabit. It would surely be peculiar to argue that a galaxy that we could once see but that has since slipped over our cosmic horizon has entered a realm that’s nonexistent, a realm that because of its permanent inaccessibility needs to be wiped off reality’s map. Even though we can’t observe or influence such realms, nor they us, they are properly included in our picture of what exists.3

It is fascinating that Greene can make a statement like this and still preclude God and the soul by "observation."

In principle, then—and make no mistake, my point here is one of principle—the mere invocation of inaccessible universes does not consign a proposal to stand outside science. To amplify this, imagine that one day we assemble a convincing experimental and observational case for string theory. Perhaps a future accelerator is able to detect sequences of string vibrational patterns and evidence for extra dimensions, while astronomical observations detect stringy features in the microwave background radiation, as well as the signatures of long stretched strings undulating through space. Suppose further that our understanding of string theory has progressed substantially, and we’ve learned that the theory absolutely, positively, incontrovertibly generates the Landscape Multiverse. Notwithstanding calls to the contrary, a theory with strong experimental and observational support, whose internal structure requires a multiverse, would lead us to conclude inexorably that the time for “giving in” had arrived.*

These are some of the most tortured intellectual gymnastics I've ever had the privilege to see.

This wouldn’t be a sharp prediction; statistical insights often aren’t. But depending on the distribution of dogs, you may be able to do much better than just pulling a number out of a hat. If your neighborhood has a highly skewed distribution, with 80 percent of the dogs being Labrador retrievers whose average weight is sixty pounds, and the other 20 percent composed of a range of breeds from Scottish terriers to poodles whose average weight is thirty pounds, then something in the fifty-five- to sixty-five-pound range would be a good bet. The dog you next encounter may be a fluffy shih tzu, but odds are it won’t be. For distributions that are even more skewed, your predictions can be more precise. If 95 percent of the dogs in your area were sixty-two-pound Labrador retrievers, then you’d be on firmer ground in predicting that the next dog you pass will be one of these. A similar statistical approach can be applied to a multiverse. Imagine we are investigating a multiverse theory that allows for a wide range of different universes—different values of force strengths, particle properties, cosmological constant values, and so on. Imagine further that the cosmological process by which these universes form (such as the creation of bubble universes in the Landscape Multiverse) is sufficiently well understood that we can determine the distribution of universes, with various properties, across the multiverse. This information has the capacity to yield significant insights. To ill...

He just unknowingly made a coherent argument for possible scientific proof of miracles.

Most universes in this scenario have a cosmological constant close to what we’ve measured in our universe, so while the range of possible values would be huge, the skewed distribution implies that the value we’ve observed is nothing special. For such a multiverse, you should be no more mystified by our universe’s having a cosmological constant value 10–123 than you should be surprised by encountering a sixty-two-pound Labrador retriever during your next stroll around the neighborhood. Given the relevant distributions, each is the most likely thing that could happen.

This directly contradicts his earlier statistical approach and presumes by faith that what we experience is, by default, the most likely outcome. Without that assumption, all this collapses.

Our very existence implies that we could never find ourselves in any of the lifeless domains, and so there’s nothing further to explain about why we don’t see their particular combination of properties.

The very definition of circularity itself. Using an anthropic assumption to prove the anthropic principle.

If we know the distribution of physical features across life-supporting universes, we can calculate such averages.

Talk about creating the world in your own image!

In fact, the words “just shy” and “nearly” don’t do the physics justice. The chance of a macroscopic body deviating from Newton’s predictions is so fantastically tiny that if you’d been keeping tabs on the cosmos for the last few billion years, the odds are overwhelming that you’d have never seen it happen.

Interesting to see the use of probability switch here suddenly and without particular reason. Universes with specific constants coming into existence? No prob, given enough time. A baseball changing its course due to its wave form? Conveniently impossible.

quantum dogma

Very appropriate choice of words.

Bohr advanced a heavyhanded remedy: evolve probability waves according to Schrödinger’s equation whenever you’re not looking or performing any kind of measurement. But when you do look, Bohr continued, you should throw Schrödinger’s equation aside and declare that your observation has caused the wave to collapse.

Wow. And they call this science? This is a creed in disguise, but without the centuries of consideration.

Imagine you’re an experimentalist with great nostalgia for your childhood in New York, so you’re measuring the positions of electrons that you inject into a miniature tabletop model of the city.

I didn't think the analogies could get more tortured. Ouch.

Our descendants are bound to create an immense number of simulated universes, filled with a great many self-aware, conscious inhabitants.

This is dependent upon a massive number of unproven, faith-based premises--not the least of which if his favored assumption that consciousness is the by-product of sheerly natural processes.

My view on mathematics periodically changes. When I’m in the throes of a mathematical investigation that’s going well, I often feel that the process is one of discovery, not invention. I know of no more exciting experience than watching the disparate pieces of a mathematical puzzle suddenly coalesce into a single coherent picture. When it happens, there’s a feeling that the picture was there all along, like a grand vista hidden by the morning fog. On the other hand, when I more objectively survey mathematics, I’m less convinced. Mathematical knowledge is the literary output of humans conversant in the unusually precise language of mathematics. And as is surely the case with literature produced in one of the world’s natural languages, mathematical literature is the product of human ingenuity and creativity. That’s not to say that other intelligent life-forms wouldn’t come upon the same mathematical results we’ve found; they very well might. But that could easily reflect similarities in our experiences (such as the need to count, the need to trade, the need to survey, and so on) and so would provide minimal evidence that math has a transcendent existence.

This is simple human nature and the ends are by no means mutually exclusive. We are finite beings with the ability to recognize, comprehend, and communicate truth. This is based in our relation to God's own character, but limited by our own frailties. Therefore, we routinely both discover and invent. We determine which and to what extent based upon our ideas' correspondence to external reality.

Although the various proposals differ widely in detail, they all suggest that our commonsense picture of reality is only part of a grander whole. And they all bear the indelible mark of human ingenuity and creativity.

They bear the mark of imagination.

As I’ve argued, however, the multiverse concept is more nuanced. We’ve seen various ways in which a theory that involves a multiverse might offer testable predictions.

But this would simply confirm the existence of something outside. We could never know anything about it that wasn't revealed on our corner.

I’ve laid out a general prescription for how a multiverse proposal might be testable, but at our current level of understanding none of the multiverse theories we’ve encountered yet meet the criteria.

Admittedly untestble and therefore currently "unscientific."

No one knows whether it will take years, decades, or even longer for observational and theoretical progress to extract detailed predictions from any given multiverse.

Blind faith that they will be testable, one day.

In the absence of compelling experimental or observational results, deciding which mathematics should be taken seriously is as much art as it is science.

Another key admission--math as art and imagination. Fascinating that he can still preclude something like theology or philosophy.